[unreadable] Individuals recovering from influenza A virus infection demonstrate an increased susceptibility to secondary bacterial pulmonary infections, particularly with the pathogens Streptococcus pyogenes and Streptococcus pneumoniae. Quite often, these secondary bacterial pneumonias are fatal, especially in geriatric and immunocompromized patients. The mechanism(s) behind this increased susceptibility to a secondary streptococcal infection are unknown. We hypothesize that this increased susceptibility to bacterial super-infection is due to a filamentous form of influenza A virus significantly facilitating the adhesion of pathogenic streptococci to respiratory mucosa. Experiments in this application will determine if filamentous influenza A virus can directly serve as a receptor for bacterial binding or if the respiratory mucosa is altered by infection with influenza virus to promote increased bacterial adherence. In parallel, we will also determine whether prior bacterial colonization can affect influenza virus replication in respiratory epithelium. [unreadable] [unreadable]